02/04/2020 11:18, Ivan Dyukov: > Hello Thomas, > > 01.04.2020 13:57, Thomas Monjalon пишет: > > 30/03/2020 09:57, Ivan Dyukov: > >> Some applications like pktgen use link speed to calculate > >> transmission rate. It limits outcome traffic to hardcoded 10G. > >> > >> This patch adds speed devarg which allows to configure > >> link speed of virtio device. > > Is it really a good idea to fake such information? > > Shouldn't it be managed differently in the application instead? > > > > > > > This is main stream of net devices. Device provides speed to > application. Application calculates the packet rate. In case of virtio, > speed is not limited by device. It could be specified by user. This > patch just gives this posibility to user.
The other possibility is to return 0 meaning unknown speed. I don't see why this information should be saved in the driver space. The user can give this information to the application, it would look more correct to me. Note: the application is controlling the devargs passed to the driver, so it can intercept such information. I understand it is easier to have the speed info at the same place in all cases. But it avoids differentiating what is a reliable info, and what is user-provided info.
